Numbers 32:29-32

Moses said to them, “If the Gadites and Reubenites prepare for battle and cross the Jordan River with you, to go before the LORD and help you take the land, give them the land of Gilead for their own. But if they do not go over armed, they will not receive it; their land will be in Canaan with you.” The Gadites and Reubenites answered, “We are your servants, and we will do as the LORD said. We will cross over into Canaan and go before the LORD ready for battle. But our land will be east of the Jordan River.”